Arrangement for long-distance conveying of thick matter

ABSTRACT

The invention concerns an arrangement for conveying thick matter, in particular liquid concrete. The arrangement comprises a pump ( 12 ) which is to be charged on the input side with thick matter to be conveyed, and a distributor ( 10 ) which can be connected via a high-pressure feed line ( 20 ) to the pressure joint ( 30 ) of the pump ( 12 ) and preferably takes the form of a tunnel shuttering distributor. The high-pressure feed line ( 20 ) is connected both on the pump side and the distributor side to a pipe-switching device ( 22, 24 ) which can in each case be switched alternatively between two connections ( 26, 32, 40, 44 ). The pump-side pipe-switching device ( 22 ) is connected at its one connection ( 26 ) to the pressure joint ( 30 ) of the pump ( 12 ) and at its other connection ( 32 ) to the pressure joint ( 36 ) of a pressure medium pump ( 16 ) which can be acted upon by low-viscosity pressure medium via a reservoir ( 18 ). The distributor-side pipe-switching device ( 24 ) is connected by one of its connections ( 40 ) to the distributor ( 10 ) an by its other connection ( 44 ) via a return line ( 45 ) to the reservoir ( 18 ) of the pressure medium pump ( 16 ). In order to prevent the distributor side form being acted upon erroneously, the distributor-side pipe-switching device ( 24 ) can be switched over as a function of a change of material occurring in the in-coming flow and conveyed material.

BACKGROUND OF THE INVENTION

The invention is related to an arrangement for long-distance conveyingof thick matter, in particular liquid concrete, comprising a thickmatter pump and a thick matter distributor which is adapted to becoupled to a pressure joint of the thick matter pump by way of a highpressure feed line.

DESCRIPTION OF THE RELATED ART

In the conveying of thick matter over great distances, tight limits areset in dependency on the viscosity of the thick matter and its frictionwith the wall of the high pressure feed line. In order to increase theattainable conveying distance, it has been proposed (EP-B 0 633 863) toreduce the friction by injecting a lubricant into the region between thewall of the feed line and a length of thick matter formed in andtransported along the feed line. This method may be applied especiallywhen conveying thick matter containing a high fraction of solids andwhen conveying distances of some hundred meters are to be attained. Withthick matter containing a high liquid fraction, such as liquid concrete,it is sought to achieve conveying distances of some thousand meters, forinstance in tunnel construction work, which cannot be achieved with theknown lubricant injection.

SUMMARY OF THE INVENTION

Based on this, it is the object of the invention to develop anarrangement of the type described above for long-distance conveying ofthick matter, in particular of liquid concrete, which makes it possibleto significantly increase the attainable conveying distance for a givenpumping capacity.

The solution according to the invention is based foremost on the idea toreduce the pressure decline along the high pressure feed line bycharging only a fraction of the total length of the high pressure feedline with the thick matter to be conveyed, while the remaining length,which may be longer than the charged length, is charged with a pressuremedium having a low viscosity and little friction with respect to thefeed line wall. In order to achieve this it is proposed according to theinvention that the high pressure feed line is connected to apipe-switching device on the pump side as well as on the distributorside, each of which pipe switching devices is adapted to bealternatingly switched to two connections, wherein the pipe switchingdevice on the pump side is connected to the pressure joint of the thickmatter pump with its one connection, and at its other connection to thepressure joint of a thick matter pump which is adapted to be chargedwith a low-viscosity pressure medium by way of a reservoir, wherein thepipe-switching device at the distributor side is connected at its oneconnection to the thick matter distributor and at its other connectionto the reservoir of the pressure medium pump by way of a return feedline, and wherein the pipe-switching device on the distributor side isadapted to be switched in response to a material change from thickmatter to pressure medium or from pressure medium to thick matteroccurring in the incoming material flow. Expediently, a sensor whichresponds to a material change in the material flow and activates theswitching operation of the pipe-switching device on the distributor sideis provided therefore.

During the steady-state operation of the conveying arrangement it is ofadvantage when the pipe-switching device on the pump side is adapted tobe switched as a function of, preferably synchronous to, thepipe-switching device on the distributor side. In this case it isachieved that always the same amount of thick matter and the same amountof pressure medium are present along the length of the conveyingdistance and that an approximately constant pressure decline occurrs fora given consistency of the thick matter.

In order to avoid a mixing of the thick matter to be conveyed and thepressure medium in the region of the separation point and to be able tobetter sense an occurrance of material change, it is proposed accordingto a preferred embodiment of the invention that a pig trap is connectedto the high pressure feed line in the region of the pipe switchingdevice on the pump side, by way of which pig trap at least onepartitioning member which is adapted to the cross section of the highpressure feed line is introduced into the high pressure feed line ateach switching of the pipe switching device on the pump side. On theother hand the high pressure feed line in the region of the pipeswitching device on the distributor side or the return feed line in theregion of the reservoir may comprise a pig trap for extracting theincoming partitioning members. In order to be able to switch the thepipe switching device on the distributor side always at the correctinstance, it is of advantage when a sensor which responds to an arrivingpartitioning member and which initiates the switching operation isdisposed in the region of the corresponding pipe switching device. Thesensor is for example designed to be a magnetic or ultrasonic sensorwhich responds to the presence of a partitioning member in the highpressure feed line.

Especially during the start-up phase and while conveying thick matter ofvarying consistency it has proven to be of advantage to provide a sensorfor initiating the switching of the pipe switching device on the pumpside, which sensor responds to a defined feed pressure of the thickmatter pump or a defined pressure decline in the high pressure feedline. With such a measure it is possible to operate the conveyingarrangement, for a given conveying capacity, always at an optimum thickmatter conveying amount. In order to avoid operating failures, it isimportant that a backflow prevention device is disposed in the feed lineleading from the pressure medium pump to the pipe switching device onthe pump side.

The long-distance conveying arrangement according to the invention isexpediently used in tunnel construction work. In this case the thickmatter distributor may be desigend to be a tunnel shutteringdistributor.

In the instance of liquid concrete being the thick matter to beconveyed, water or a concrete-water-mixture or a low-viscosity liquidpolymer is used as a pressure medium.

In the following the invention is further described with reference to anembodiment schematically shown in the drawing, in which:

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a schematic diagram of a conveying arrangement for liquidconcrete for tunnel construction work;

FIG. 2 shows a detail of the arrangement according to FIG. 1, the pipeswitching devices being switched with respect to FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The stationary pumping arrangement schematically shown in the drawing isintended to be used to convey concrete over a long distance to a tunnelshuttering distributor 10 located in a tunnel 11. It consistsessentially of a thick matter pump 12 which is preferably designed to bea two-cylinder piston pump and which is charged with liquid concretefrom a large material supply container 14, a pressure medium pump 16which is designed to be a two-cylinder piston pump and which is chargedwith a pressure medium, for example a bentonite-water mixture, from alarge reservoir 18, an approximately 5000 meters long high pressure feedline 20 which extends between the two stationary pumps 12, 16 on the onehand and the tunnel shuttering distributor 10 on the other hand, and twopipe switching devices 22, 24, one of which is connected to the pumpside end and the other one of which is connected to the distributor sideend of the high pressure feed line 20 and which are adapted to beswitched between two connections. The pipe switching device 22 on thepump side is connected with its one connection 26 to the pressure joint30 of the thick matter pump 12 by way of a feed line 28, while thesecond connection 32 of the pipe switching device 22 is connected to thepressure joint 36 of the pressure medium pump 16 by way of a feed line34. For safety reasons a backflow prevention device 38 is disposed inthe feed line 34, which permits flow from the pressure medium pump 16 tothe pipe switching device 22 and prevents flow in the oppositedirection.

The pipe switching device 24 on the distributor side is connected to thetunnel shuttering distributor 10 with its one connection 40 by way of aconcrete feed line 42, while it is connected to the reservoir 18 by wayof a return feed line 45 for the bentonite-water mixture. In theposition shown in FIG. 1, the high pressure feed line 20 communicates byway of the pipe switching device 22 with the pressure medium pump 16 andby way of the pipe switching device 24 with the reservoir 18, while inthe position shown in FIG. 2, the high pressure feed line 20 isconnected by way of the pipe switching device 22 with the thick matterpump 12 and by way of the pipe switching device 24 with the tunnelshuttering distributor 10. By suitably controlling the pipe switchingdevice 22 it is possible to alternately charge the high pressure feedline 20 with concrete and the pressure medium. In the embodiment shownin FIG. 2, liquid concrete is present in a feed line section 46 having alength of approximately 2000 meters and pressure medium is present inthe feed line section 48 having a length of 3000 meters. At theseperation point between the concrete and the pressure medium there is apartitioning member 50 designed to be a pig, which prevents a mixing ofconcrete and pressure medium and which is easily detected from theoutside in order to effect a switching of the pipe switching device 24on the distributor side. In order to facilitate the latter, thepartitioning member 50 can be fitted with a magnetic or magnetizablematerial which can be detected by a magnetic sensor 52 located in thevicinity of the pipe switching device 24 on the distributor side andwhich can be used to trigger a switching signal.

The partitioning members 50 are expediently brought into the highpressure feed line 20 during each switching of the pipe switching device22 by way of a pig trap 54 and are extracted from the high pressure feedline 20 during the switching of the pipe switching device 24 on thedistributor side by way of a pig trap 56. In principle it is alsopossible to dispose the pig trap 56 in the region of the reservoir 18instead of at the pipe switching device 24. In this case thepartitioning member 50 is transported back to the pump side by way ofthe return feed line 45.

In summary the following is to be stated: The invention is related to anarrangement for long-distance conveying of thick matter, in particularof liquid concrete. The arrangement comprises a thick matter pump 12,the input of which is adapted to be charged with the thick matter to beconveyed, and a thick matter distributor 10 which is adapted to becoupled to a pressure joint 30 of the thick matter pump 12 by way of ahigh pressure feed line 20 and which is preferably designed to be atunnel shuttering distributor. The high pressure feed line 20 isconnected to a pipe-switching device 22, 24 on the pump side as well ason the distributor side, each of which pipe switching devices is adaptedto be alternatingly switched to two connections 26, 32, 40, 44. In this,the pipe switching device 22 on the pump side is connected to thepressure joint 30 of the thick matter pump 12 with its one connection26, and at its other connection 32 to the pressure joint 36 of a thickmatter pump 16 which is adapted to be charged with a low-viscositypressure medium by way of a reservoir 18. On the other hand, thepipe-switching device 24 at the distributor side is connected at its oneconnection 40 to the thick matter distributor 10 and at its otherconnection 44 to the reservoir 18 of the pressure medium pump 16 by wayof a return feed line 45. In order to prevent a mischarging on thedistributor side, the pipe-switching device 24 on the distributor sideis adapted to be switched in response to a material change occurring inthe incoming material flow.

What is claimed is:
 1. An arrangement for long-distance conveying ofthick matter, comprising: a thick matter pump (12), the input of whichis adapted to be charged with the thick matter to be conveyed, theoutput of which is connected via a connection (26) to the thick matterinput of a first pipe switching device (22), a pressure medium pump (16)which is adapted to be charged with a low-viscosity pressure medium byway of a reservoir (18), the output of which is connected via aconnection (32) to the pressure medium input of said first pipeswitching device (22), a single high pressure conveyor line (20), saidfirst pipe switching device connected via said high pressure conveyorline (20) to a second pipe switching device (24), said first pipeswitching device adapted to alternatingly connect said high pressureconveyor line (20) to said first pipe switching device thick matterinput and to said first pipe switching device pressure medium input;said second pipe switching device (24) adapted to switching theconnection of said high pressure conveyor line (20) alternatinglybetween two outputs (40, 44), wherein one of said second pipe switchingdevice (24) outputs (40) is connected to a thick matter distributor (10)and the other of said outputs (44) is connected to the reservoir (18) ofthe pressure medium pump (16) by way of a return feed line (45), andwherein said second pipe-switching device (24) is adapted to beingswitched in response to a material change occurring in the incomingmaterial flow.
 2. The arrangement of claim 1, further including a sensor(52) for sensing a material change in the material flow and sending asignal which activates the switching operation of said secondpipe-switching device.
 3. The arrangement of claim 2, wherein the sensor(52) is one of (a) a magnetic and (b) an ultrasonic sensor whichresponds to the presence of a partitioning member (50) in the highpressure conveyor line (20).
 4. The arrangement of claim 1, wherein theswitching of said first and second pipe-switching devices aresynchronized.
 5. The arrangement of claim 1, further comprising a pigtrap (54) connected to the high pressure conveyor line (20) downstreamof the first pipe switching device (22), by way of which pig trap atleast one partitioning member (50), which is adapted to the crosssection of the high pressure conveyor line, is introduced into the highpressure conveyor line (20) at each switching of the first pipeswitching device (22).
 6. The arrangement of claim 5, further includinga sensor (52) provided upstream of the second switching device (24),which sensor (52) responds to an arriving partitioning member (50) andsends a signal which initiates the switching operation of the secondpipe switching device (24).
 7. The arrangement of claim 5, wherein oneof (a) the high pressure conveyor line (20) upstream of the second pipeswitching device (24) and (b) the return feed line (45) upstream of thereservoir (18) comprises a pig trap (56) for extracting the incomingpartitioning members (50).
 8. The arrangement of claim 1, furthercomprising a sensor for sensing one of (a) a predetermined feed pressureof the thick matter pump (14) and (b) a predetermined pressure drop inthe high pressure conveyor line (20) and, upon so sensing, sending asignal initiating the switching of the first pipe switching device (22).9. The arrangement of claim 1, wherein a backflow prevention device (38)is disposed between the pressure medium pump (16) and the first pipeswitching device (22).
 10. The arrangement of claim 1, wherein the thickmatter distributor (10) is a tunnel shuttering distributor.
 11. Thearrangement of claim 1, wherein said thick matter is liquid concrete,and wherein said pressure medium is selected from the group consistingof water, a concrete-water-mixture and a low-viscosity liquid polymer.